ИСТИНА

Detonation nanodiamonds (NDs) gain much attention for biomedical and clinical applications, and high-technology purposes due to their unique properties. Especially important are biological and medical applications. NDs can be used as contrast agents, antibiotics, biolables; they are promising against cancer, in cellular surgery, as antioxidants, enterosorbents [1]. Aqueous colloidal solutions of nanodiamonds are the most suitable for medicine. However, many ND properties, which are relevant for such uses depend on their production, purification, and certification technology. Moreover, it is strongly necessary for biomedical purposes to know concentration of nanodiamonds in solutions and their colloidal particle and aggregate sizes. The development of analytical techniques is the first and crucial step to make ND properties traceable and to improve the production technology. Recently, the progress in laser technologies has provided a sound basis for compact optical schemes and commercial applications of photoacoustic (PAS) and photothermal (PTS) spectroscopies in analytical and physical chemistry. In this study, we used PAS/PTS measurements for nanodiamond suspensions at high and trace level of constituents in various media (aqueous solutions and organic solvents). We used PAS/PTS in their state-of-the-art techniques—multiwavelength, scanning and transient—are used for complex investigation and analysis (chemical analysis and the estimation of physicochemical properties and size) of NDs from total of 20 tradmarks from various manufactureres and their aqueous dispersions. The estimation of the cluster size and the possibilities to determine subnanogram amounts NDsby these techniques are shown. We also used PAS/PTS for estimating size and concentrational dependences in ND dispersions. Aqueous ND disperse media are characterized by a multitude of conversion mechanisms, with the main feature of their simultaneous and competing character. Moreover, the existing of particles with constantly changing configuration provides a random constituent of the signal. These features were observed as functions of dynamic (response profile) and statistic (amplitude fluctuation) parameters of PAS/PTS signals and disperse-phase parameters. The estimation of the cluster size from two techniques—transient and imaging PTS–giving concordant values and agreeing with dynamic light-scattering data are very invigorating. In addition, we studied high-energy laser radiation influence on nanodiamonds dispersed systems. More results will be presented at the conference. ACKNOWLEDGEMENTS The Russian Foundation for Basic Research, grants nos. 13-03-00535А and 12-03-31569 mol_a and the Ministry of Science and Technology of Russian Federation, contract no. 16.740.11.0471.